U.S. patent application number 12/603132 was filed with the patent office on 2010-06-17 for toner for developing electrostatic latent image and method of preparing the toner.
This patent application is currently assigned to SAMSUNG ELECTRONICS CO., LTD.. Invention is credited to Jae-Hwan Kim, Tae-Hoe Koo, Jun-Young Lee, Yo-Da Shin.
Application Number | 20100151376 12/603132 |
Document ID | / |
Family ID | 42240958 |
Filed Date | 2010-06-17 |
United States Patent
Application |
20100151376 |
Kind Code |
A1 |
Kim; Jae-Hwan ; et
al. |
June 17, 2010 |
TONER FOR DEVELOPING ELECTROSTATIC LATENT IMAGE AND METHOD OF
PREPARING THE TONER
Abstract
Disclosed are a toner for developing an electrostatic latent
image and a method of preparing the toner. The toner may include a
latex, a colorant and a releasing agent, and may further include
sulfur (S), iron (Fe) and silicon (Si). The [S]/[Fe] ratio may be
within the range between about 5.0.times.10.sup.-4 and about
5.0.times.10.sup.-2. The [Si]/[Fe] ratio may be within the range of
between about 5.0.times.10.sup.-4 and about 5.0.times.10.sup.-2.
[S], [Fe] and [Si] are the amounts of S, Fe and Si measured by
X-ray fluorescence spectrometry, respectively.
Inventors: |
Kim; Jae-Hwan; (Seoul,
KR) ; Lee; Jun-Young; (Seoul, KR) ; Shin;
Yo-Da; (Incheon Metropolitan City, KR) ; Koo;
Tae-Hoe; (Seoul, KR) |
Correspondence
Address: |
DLA PIPER LLP US
P. O. BOX 2758
RESTON
VA
20195
US
|
Assignee: |
SAMSUNG ELECTRONICS CO.,
LTD.
Suwon-Si
KR
|
Family ID: |
42240958 |
Appl. No.: |
12/603132 |
Filed: |
October 21, 2009 |
Current U.S.
Class: |
430/108.7 ;
430/137.13 |
Current CPC
Class: |
G03G 9/08724 20130101;
G03G 9/08722 20130101; G03G 9/08782 20130101; G03G 9/0806 20130101;
G03G 9/08704 20130101; G03G 9/08755 20130101; G03G 9/0827 20130101;
G03G 9/08793 20130101; G03G 9/08713 20130101; G03G 9/0819 20130101;
G03G 9/08726 20130101 |
Class at
Publication: |
430/108.7 ;
430/137.13 |
International
Class: |
G03G 9/093 20060101
G03G009/093 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 17, 2008 |
KR |
10-2008-0128619 |
Claims
1. A toner comprising a latex, a colorant, and a releasing agent,
wherein the toner further comprises sulfur (S), iron (Fe) and
silicon (Si), wherein the [S]/[Fe] ratio is in the range of about
5.0.times.10.sup.-4 to about 5.0.times.10.sup.-2, wherein the
[Si]/[Fe] ratio is in the range of about 5.0.times.10.sup.-4 to
about 5.0.times.10.sup.-2, and wherein [S], [Fe] and [Si] denote
respectively the amounts of S, Fe and Si each measured using an
X-ray fluorescence spectrometry.
2. The toner of claim 1, wherein each of [S] and [Fe] is in the
range of about 3 to about 30,000 ppm.
3. The toner of claim 1, wherein the releasing agent comprises a
mixture of a paraffin-based wax with an ester-based wax; or an
ester group-containing paraffin-based wax.
4. The toner of claim 3, wherein the releasing agent comprises a
mixture of a paraffin-based wax and an ester-based wax, and wherein
the amount of the ester-based wax is in the range of about 5 to
about 39 parts by weight % based on the total weight of the
releasing agent.
5. The toner of claim 1, wherein the toner has an average particle
diameter in the range of about 3 to about 8 .mu.m.
6. The toner of claim 1, wherein the toner has an average
circularity in the range of about 0.940 to about 0.990.
7. The toner of claim 1, wherein the toner has a volume average
particle diameter distribution coefficient (GSDv) of about 1.30 or
less and a number average particle diameter distribution
coefficient (GSDp) of about 1.30 or less.
8. A method of preparing a toner, comprising: mixing a primary
latex particle, a colorant dispersion and a releasing agent
dispersion to form a mixed solution; adding an agglomerating agent
to the mixed solution to form a primary agglomerated toner; and
coating the primary agglomerated toner with a secondary latex to
form a secondary agglomerated toner, the secondary latex being
prepared by polymerizing at least one polymerizable monomer on the
primary agglomerated toner, wherein the toner comprises S, Fe and
Si, the [S]/[Fe] ratio being in the range of about
5.0.times.10.sup.-4 to about 5.0.times.10.sup.-2, the [Si]/[Fe]
ratio being in the range of about 5.0.times.10.sup.-4 to about
5.0.times.10.sup.-2, [S], [Fe] and [Si] being respectively the
amounts of S, Fe and Si measured using an X-ray fluorescence
spectrometry.
9. The method of claim 8, wherein the primary latex particle
comprises polyester, a polymer formed by polymerizing at least one
polymerizable monomer, or a mixture thereof.
10. The method of claim 8, further comprising: coating the
secondary agglomerated toner with a tertiary latex, wherein the
tertiary latex is prepared by polymerizing at least one
polymerizable monomer on the secondary agglomerated toner.
11. The method of claim 8, wherein the at least one polymerizable
monomer comprises at least one monomer selected from styrene-based
monomers, acrylic acids, methacrylic acid, derivatives of
(meth)acrylic acids, ethylenically unsaturated monoolefines,
halogenated vinyls, vinyl esters, vinyl ethers, vinyl ketones and
nitrogen-containing vinyl compounds.
12. The method of claim 8, wherein the releasing agent dispersion
comprises a mixture of a paraffin-based wax with an ester-based
wax; or an ester group-containing paraffin-based wax.
13. The method of claim 8, wherein the agglomerating agent
comprises a Si and Fe containing metal salt.
14. The method of claim 13, wherein the agglomerating agent
comprises polysilica iron.
15. The method of claim 8, wherein the agglomerating agent is added
to the mixed solution at a pH level in the range of about 0.1 to
about 2.0.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATION
[0001] This application claims the benefit of Korean Patent
Application No. 10-2008-0128619, filed on Dec. 17, 2008 in the
Korean Intellectual Property Office, the disclosure of which is
hereby incorporated by reference in its entirety for all
purposes.
TECHNICAL FIELD
[0002] The present disclosure generally relates to toner for
developing an electrostatic latent image and methods of preparing
the toner.
BACKGROUND OF RELATED ART
[0003] For electrophotographic processes or electrostatic recording
process, developers that visualize electrostatic images or
electrostatic latent images may be classified into two-component
developers and one-component developers. Two-component developers
are composed of toner and carrier particles; whereas one-component
developers are substantially composed of only toner. That is,
one-component developers do not use carrier particles.
One-component developers may be further classified into magnetic
developers and nonmagnetic developers, in which magnetic developers
contain a magnetic component while nonmagnetic developers do not.
In addition, fluiding agents may be added to nonmagnetic
one-component developers in order to improve the fluidity of the
toner. Examples of fluiding agents include, but are not limited to,
colloidal silica and the like.
[0004] In general, toners contain colored particles, which may be
obtained by dispersing a pigment such as carbon black or other
additives in latex. These toner may be prepared using a grinding
method (sometimes also referred to as a pulverizing method) or a
polymerizing method. In the grinding method, a synthesized resin, a
colorant and optionally other additives are dissolved and mixed
together. The resulting mixture is ground. The particles resulting
from the grinding or pulverization are classified or sorted in
order to obtain particles having a desired diameter. In the
polymerizing method, a polymerizable monomer, a colorant, a
polymerization initiator and optionally other additives, such as,
for example, a crosslinking agent or an antistatic agent, are
homogeneously dissolved together or are dispersed to form a
polymerizable monomer composition. The polymerizable monomer
composition may be dispersed with an agitator in an aqueous
dispersion medium containing a dispersion stabilizer so as to form
droplet particles of the composition. The temperature of the
composition may be increased and a suspension-polymerization
process may be performed on the composition to obtain color
polymerization particles having the desired particle diameters,
that is, the desired polymerization toner.
[0005] Toner for developing an electrostatic latent image described
above may contain impurities, which may be the source of an
unpleasant odor. For example, aromatic impurities having low
molecular weights may generate an unpleasant odor when the toner is
used or when a packaged toner is open.
[0006] Toner may be fixed to a surface of a medium (e.g., a sheet
of paper) through the use of a fixing method. For example, fixing
methods include methods such as a compression fixing method, a heat
fixing method, or a combination thereof. Examples of the heat
fixing method include an oven fixing method, a flash fixing method,
and a heating roller fixing method. The heating roller fixing
method is widely used in electrophotographic copiers and printers.
When a toner image on a medium is fused onto a surface of a the
medium by using the heating roller fixing method, the toner image
can be quickly fixed with high thermal efficiency. In particular,
the heating roller fixing method is very useful for high-speed
copying and printing.
[0007] Since the heating roller fixing method includes heating of
the toner, small amounts of materials contained in the toner may
also be discharged into the surrounding atmosphere resulting in an
unpleasant odor. With the reductions in the sizes of copiers and
printers, they use in an office or home setting has become more
prevalent, increasing the likelihood of a user being exposed to the
unpleasant odor generated from toner. The human sense of smell may
be as low as 0.1 ppm or less.
[0008] The unpleasant odor induced from toner may be reduced by
decreasing the impurities, for example, contained in the binder
resin. For example, the unpleasant odor may be reduced by
decreasing the monomer residue in the binder resin of the toner.
The oxidation product of benzaldehyde contained in toner has also
been reported as a source of an unpleasant odor. Accordingly, there
have been many efforts made in an attempt to reduce the amount of
benzaldehyde present in toner. In addition, much research has been
conducted into the feasibility of adding to toner a material that
reacts with or adsorbs the unpleasant odor. For example, these
materials include but are not limited to an alkyl betaine compound,
catechin, and metal phthalocyanine. However, there is still a need
to develop toner that generates less of an unpleasant odor while
maintaining the other desirable properties of the toner.
SUMMARY OF THE DISCLOSURE
[0009] According to an aspect of the present disclosure, there is
provided a toner that may comprise a latex, a colorant and a
releasing agent, and that may further include sulfur (S), iron (Fe)
and silicon (Si). The [S]/[Fe] ratio may be from about
5.0.times.10.sup.-4 to about 5.0.times.10.sup.-2. The [Si]/[Fe]
ratio may be from about 5.0.times.10.sup.-4 to about
5.0.times.10.sup.-2. [S], [Fe] and [Si] denote the amounts of S, Fe
and Si, respectively, each measured using an X-ray fluorescence
spectrometry.
[0010] Each of the [S] and the [Fe] may be in the range of about 3
to about 30,000 ppm.
[0011] The releasing agent may comprise a mixture of a
paraffin-based wax with one of an ester-based wax; or an ester
group-containing paraffin-based wax.
[0012] The releasing agent may for example comprise a mixture of a
paraffin-based wax and an ester-based wax. The amount of the
ester-based wax may be in the range of about 5 to about 39 parts by
weight % based on the total weight of the releasing agent.
[0013] The toner may have an average particle diameter in the range
of about 3 to about 8 .mu.m.
[0014] The toner may have an average circularity in the range of
about 0.940 to about 0.990.
[0015] The toner may have a volume average particle diameter
distribution coefficient (GSDv) of about 1.30 or less and a number
average particle diameter distribution coefficient (GSDp) of about
1.30 or less.
[0016] According to another aspect of the present disclosure, a
method of preparing a toner may be provided to include the steps
of: mixing a primary latex particle, a colorant dispersion and a
releasing agent dispersion to form a mixed solution; adding an
agglomerating agent to the mixed solution to form a primary
agglomerated toner; and coating the primary agglomerated toner with
a secondary latex to form a secondary agglomerated toner, the
secondary latex being prepared by polymerizing at least one
polymerizable monomer on the primary agglomerated toner. The toner
may comprise S, Fe and Si. The [S]/[Fe] ratio may be in the range
of about 5.0.times.10.sup.-4 to about 5.0.times.10.sup.-2. The
[Si]/[Fe] ratio may be in the range of about 5.0.times.10.sup.-4 to
about 5.0.times.10.sup.-2. [S], [Fe] and [Si] may be respectively
the amounts of S, Fe and Si as measured using an X-ray fluorescence
spectrometry.
[0017] The primary latex particle may comprise polyester, a polymer
formed by polymerizing at least one polymerizable monomer, or a
mixture thereof.
[0018] The method may further comprise coating the secondary
agglomerated toner with a tertiary latex. The tertiary latex may be
prepared by polymerizing at least one polymerizable monomer on the
secondary agglomerated toner.
[0019] The at least one polymerizable monomer may comprise at least
one monomer selected from styrene-based monomers, acrylic acids,
methacrylic acid, derivatives of (meth)acrylic acids, ethylenically
unsaturated monoolefines, halogenated vinyls, vinyl esters, vinyl
ethers, vinyl ketones and nitrogen-containing vinyl compounds.
[0020] The releasing agent dispersion may comprise a mixture of a
paraffin-based wax with an ester-based wax; or an ester
group-containing paraffin-based wax.
[0021] The agglomerating agent may comprises a Si and Fe containing
metal salt.
[0022] The agglomerating agent may comprise polysilica iron.
[0023] The agglomerating agent may be added to the mixed solution
at a pH level in the range of about 0.1 to about 2.0.
[0024] According to yet another aspect of the present disclosure, a
method of forming an image may be provided to include the steps of
attaching toner to a surface of a photoreceptor on which an
electrostatic latent image is formed so as to form a visible image;
and transferring the visible image onto a print medium. The toner
may comprise a latex, a colorant and a releasing agent, and may
further include sulfur (S), iron (Fe) and silicon (Si). The
[S]/[Fe] ratio may be from about 5.0.times.10.sup.-4 to about
5.0.times.10.sup.-2. The [Si]/[Fe] ratio may be from about
5.0.times.10.sup.-4 to about 5.0.times.10.sup.-2. [S], [Fe] and
[Si] denote the amounts of S, Fe and Si, respectively, each
measured using an X-ray fluorescence spectrometry.
[0025] According even yet another aspect of the present disclosure,
a toner supplying apparatus may be provided to include a toner tank
and a supplying part. The toner tank may define a volume into which
to receive a supply of toner. The supplying part may be arranged to
project into the volume defined by the toner tank, and may have a
toner outlet through which toner is discharge out of the toner
tank. The toner may comprise a latex, a colorant and a releasing
agent, and may further include sulfur (S), iron (Fe) and silicon
(Si). The [S]/[Fe] ratio may be from about 5.0.times.10.sup.-4 to
about 5.0.times.10.sup.-2. The [Si]/[Fe] ratio may be from about
5.0.times.10.sup.-4 to about 5.0.times.10.sup.-2. [S], [Fe] and
[Si] denote the amounts of S, Fe and Si, respectively, each
measured using an X-ray fluorescence spectrometry.
[0026] The toner supplying apparatus may further comprise a toner
agitating member rotatably disposed inside the toner tank to cause
a movement of toner within the toner tank. The toner agitating
member may be of such shape and size so as to be capable of causing
the movement of toner located on a top surface of the supplying
part.
[0027] The toner agitating member may comprise a rotational shaft
about which the agitating member rotates and a film extending
radially outward from the rotational shaft. The film may be divided
into first and second sections, the first section of the film being
configured come into an interfering contact with the top surface of
the supplying part and being bendable responsive to the interfering
contact independently of the second section.
[0028] According to still yet another aspect of the present
disclosure, an image forming apparatus may be provided to comprise
an image carrier, a toner supplying unit and a toner transferring
unit. The image carrier may have a surface capable of supporting
thereon an electrostatic latent image. The toner supplying unit may
be configured to supply toner onto the surface of the image carrier
to thereby develop the electrostatic latent image into a toner
image. The toner transferring unit may be configured to transfer
the toner image from the surface of the image carrier to a print
medium. The toner may comprise a latex, a colorant and a releasing
agent, and may further include sulfur (S), iron (Fe) and silicon
(Si). The [S]/[Fe] ratio may be from about 5.0.times.10.sup.-4 to
about 5.0.times.10.sup.-2. The [Si]/[Fe] ratio may be from about
5.0.times.10.sup.-4 to about 5.0.times.10.sup.-2. [S], [Fe] and
[Si] denote the amounts of S, Fe and Si, respectively, each
measured using an X-ray fluorescence spectrometry.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Various features and advantages of the present disclosure
will become more apparent by describing in detail exemplary
embodiments thereof with reference to the attached drawings in
which:
[0030] FIG. 1 is a perspective view of a toner supplying unit
according to an embodiment of the present disclosure; and
[0031] FIG. 2 is a schematic view of an imaging apparatus including
a toner manufactured according to an embodiment of the present
disclosure.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0032] The present disclosure will now be described more fully with
reference to the accompanying drawings, in which exemplary
embodiments of the present disclosure are shown.
[0033] According to the present disclosure, toner for developing an
electrostatic latent image may include latex, a colorant and a
releasing agent, and may further include sulfur (S), iron (Fe) and
silicon (Si). The [S]/[Fe] ratio may be from about
5.0.times.10.sup.-4 to about 5.0.times.10.sup.-2. The [Si]/[Fe]
ratio may be from about 5.0.times.10.sup.-4 to about
5.0.times.10.sup.-2. [S], [Fe] and [Si] denote the amounts of S, Fe
and Si, respectively, measured by an X-ray fluorescence
spectrometry.
[0034] According to an embodiment, the [S] may correspond to the
amount of S contained in an S-containing compound, which may act as
a chain transfer agent for adjusting a latex molecular distribution
when the latex is prepared.
[0035] According to an embodiment, the [Fe] may correspond to the
amount of Fe contained in an agglomerating agent, which may be used
to agglomerate the latex, the colorant and the releasing agent when
the toner is being prepared. Thus, the [Fe] may affect the
agglomeration properties, particle distribution, and/or the
particle size of agglomerated toner. In this regard, the
agglomerated toner may be a precursor for preparing the final
toner.
[0036] According to an embodiment, the [Si] may correspond to the
sum of the amount of Si contained in polysilica contained in an
agglomerating agent and/or the amount of Si contained in silica
that is externally added to secure the flowability of toner. Thus,
the [Si] may affect the agglomeration properties, particle
distribution, and/or the particle size of the agglomerated toner as
well as the flowability of the toner.
[0037] According to an embodiment, the [S]/[Fe] ratio may be, for
example, from about 5.0.times.10.sup.-4 to about
5.0.times.10.sup.-2, or from about 8.0.times.10.sup.-4 to about
3.0.times.10.sup.-2, or from about 1.0.times.10.sup.-3 to about
1.0.times.10.sup.-2. If the [S]/[Fe] ratio is within these ranges,
and the molecular weight and the degree of agglomeration are
appropriately controlled, the desired particle size and particle
size distribution may be obtained while less unpleasant odor may be
generated. If the [Si]/[Fe] ratio is within these ranges, the
flowability of the toner may be increased, and the inside of the
printer may also be protected from contamination.
[0038] According to an aspect of the present disclosure, there is
provided a method of preparing a toner for developing an
electrostatic latent image, which may include the steps of a)
mixing a primary latex particle, a colorant dispersion and a
releasing agent dispersion to provide a mixed solution; b) adding
an agglomerating agent to the mixed solution to prepare a primary
agglomerated toner; c) coating the primary agglomerated toner with
a secondary latex to prepare a secondary agglomerated toner. The
secondary latex may be prepared by polymerizing at least one
polymerizable monomer. The toner may include S, Fe, and Si. The
[S]/[Fe] ratio may be in the range from about 5.0.times.10.sup.-4
to about 5.0.times.10.sup.-2. The [Si]/[Fe] ratio may be from about
5.0.times.10.sup.-4 to about 5.0.times.10.sup.-2. The [S], [Fe] and
[Si] denote the amount of S measured by X-ray fluorescence
spectrometry, the amount of Fe measured by X-ray fluorescence
spectrometry and the amount of Si measured by X-ray fluorescence
spectrometry, respectively.
[0039] Examples of the agglomerating agent include but are not
limited to NaCl, MgCl.sub.2, MgCl.sub.2.8H.sub.20,
[Al.sub.2(OH).sub.nCl.sub.6-n].sub.m
(Al.sub.2(SO.sub.4).sub.3.18H.sub.2O), polyaluminum chloride (PAC),
polyaluminum sulfate (PAS), polyaluminum sulfate silicate (PASS),
ferrous sulfate, ferric sulfate, ferric chloride, calcium
hydroxide, calcium carbonate and Si and/or Fe-containing metal
salts, and the like. However, the agglomerating agent is not
limited to these examples.
[0040] The amount of the agglomerating agent may be, for example,
from about 0.1 to about 10 parts by weight, or from about 0.5 to
about 8 parts by weight, or from about 1 to about 6 parts by
weight, based on 100 parts by weight of the primary latex particle.
If the amount of the agglomerating agent is within these ranges,
the agglomeration effect and toner particle size distribution may
advantageously be improved, the chargeability of the toner may be
improved, and/or the internal contamination of the printer may be
reduced.
[0041] According to an embodiment of the method of preparing toner
for developing an electrostatic latent image, the agglomerating
agent may be a Si and/or Fe containing metal salt. The amount of
each of Si and Fe may be, for example, from about 3 to about 30,000
ppm, or from about 30 to about 25,000 ppm, or from about 300 to
about 20,000 ppm. If the amount of each of Si and Fe are within
these ranges, the chargeability of the toner may be improved,
and/or the internal contamination of the printer may be
reduced.
[0042] The Si and Fe containing metal salt may include, for
example, polysilica iron. Due to the increased ionic strength of
the toner by adding the Si and Fe containing metal salts, the size
of the primary agglomerated toner may be increased. The Si and Fe
containing metal salt may also be, for example, polysilicate iron.
Available examples of the Si and Fe containing metal salts include
but are not limited to PSI-025, PSI-050, PSI-075, PSI-100, PSI-200,
and PSI-300, and the like (available from Suido Kiko Kaisha, Ltd.
of Tokyo, Japan).
[0043] Table 1 shows the physical properties and compositions of
PSI-025, PSI-050, PSI-075, PSI-100, PSI-200, and PSI-300.
TABLE-US-00001 TABLE 1 Type PSI-025 PSI-050 PSI-085 PSI-100 PSI-200
PSI-300 Silica/Fe mole ratio 0.25 0.5 0.85 1 2 3 (Si/Fe) Main Fe
5.0 3.5 2.5 2.0 1.0 0.7 component (wt %) concentration SiO2 1.4 1.9
2.0 2.2 (wt %) pH(1 w/v %) 2-3 Specific gravity 1.14 1.13 1.09 1.08
1.06 1.04 (20.degree. C.) Viscosity (mPa S) 2.0 or more Average
molecular 500,000 weight (Dalton) External appearance Yellowish
brown transparent liquid
[0044] The use of a Si and Fe-containing metal salts as an
agglomerating agent according to an embodiment of the methods for
preparing an electrophotographic toner, allows for the reduction in
size of the toner particles as well as control over the shape of
the particles.
[0045] According to an embodiment, the agglomerating agent having a
pH level that ranges from about 0.1 to about 2.0, or from about 0.3
to about 1.8, or from about 0.5 to about 1.6, may be used. When an
agglomerating agent having the pH level that is within the above
ranges is added, then the handing efficiency may be increased, the
unpleasant odor may be controlled, and/or the agglomeration
efficiency may be increased.
[0046] According to an embodiment of the present disclosure, the
volume average particle diameter distribution coefficient of the
toner may be, for example, from about 3 to about 8 .mu.m, or from
about 4 to about 7.5 .mu.m, or from about 4.5 to about 7 .mu.m; and
the average circularity of the toner may be, for example, from
about 0.940 to about 0.990, or from about 0.945 to about 0.985, or
from about 0.950 to about 0.980.
[0047] In general, the smaller the toner particle size is, the
higher the resolution and the higher the image quality of an image
may be. However, when the transfer speed and the necessary cleaning
force are taken into consideration, an excessively small toner
particle size may not be desirable. Thus, it may be important to
have an appropriate toner particle size for an optimal
performance.
[0048] The volume average particle diameter of the toner may be
measured by electrical impedance analysis, for example. If the
volume average particle diameter of the toner is kept within the
range described above, it may be easier to clean the photoreceptor,
the toner particles may be charged with an improved uniformity, the
toner particles may be less likely to adhere together into lumps,
and it may thus be easier to regulate the toner layer, e.g., using
a doctor blade, any one of which improvements may contribute in
enabling higher resolution and/or quality images. In addition, with
the volume average particle diameter of the toner being within the
above described ranges, the production yield may also increase
during mass-production of the toner.
[0049] If the average circularity of the disclosed toner is within
the range described above, since the image developed on the
transfer medium may have a sufficient coverage ratio, a lesser
amount of toner consumption may be required in order to obtain a
desired image concentration. Further, occurrences of non-uniformity
in the toner layer coating the development sleeve due to an
excessive amount of toner being supplied onto the sleeve may also
be reduced.
[0050] The circularity of the toner can be measured, for example
according to an embodiment, using a SYSMEX FPIA-3000 (available
from Sysmex Corporation of Kobe, Japan) according to the following
equation:
Circularity=2.times.(.pi..times.area).sup.0.5/circumference.
[0051] The circularity may be from 0 to 1. As the circularity
approaches 1, the toner particle shape becomes more circular.
[0052] The toner particle distribution coefficient may be a volume
average particle diameter distribution coefficient GSDv or a number
average particle diameter distribution coefficient GSDp. The GSDv
and the GSDp may be measured in the following manner.
[0053] First, a toner particle diameter distribution may be
obtained using toner particle diameters measured using a Multisizer
III (available from Beckman Coulter Inc. of Fullerton, Calif.,
U.S.A.). The toner particle diameter distribution is divided at
predetermined particle diameter ranges (channels). With respect to
the respective divided particle diameter ranges (channels), the
cumulative volume distribution of toner particles and the
cumulative number distribution of toner particles are measured,
wherein, in each of the cumulative volume and number distributions,
the particle size in each distribution is increased in a direction
from the left to the right. A particle diameter at 16% of the
respective cumulative distributions is defined as a volume average
particle diameter D16v and a number average particle diameter D16p,
respectively. A particle diameter at 50% of the respective
cumulative distributions is defined as a volume average particle
diameter D50v and a number average particle diameter D50p,
respectively. A particle diameter at 84% of the respective
cumulative distributions is defined as a volume average particle
diameter D84v and a number average particle diameter D84p.
[0054] In this case, GSDv is defined as (D84v/D16v).sup.0.5, and
GSDp is defined as (D84p/D16p).sup.0.5. In this regard, the GSDv
and GSDp is each, for example, from about 1.30 or less, or about
1.15 to about 1.30, or about 1.20 to about 1.25. If the GSDv and
GSDp is within the ranges described above, the toner particle
diameters may be uniform.
[0055] In the method of preparing a toner according to an
embodiment, the primary latex may be polyester, a polymer prepared
by polymerizing at least one polymerizable monomer, or a mixture
thereof (hybrid). When the primary latex is a polymer, at least one
polymerizable monomer may be polymerized together with a releasing
agent such as wax in the polymerizing process, or the polymer may
be mixed with the releasing agent.
[0056] The polymerizing process may be an emulsion polymerization
distribution process. As a result of the emulsion polymerization
distribution process, the primary latex particles may have a
particle size of about 1 .mu.M or less, for example, or from about
100 to about 300 nm, or from about 150 to about 250 nm.
[0057] The polymerizable monomer used herein may include at least
one monomer such as styrene, vinyl toluene, or
.alpha.-methylstyrene; acrylic acids, methacrylic acids;
derivatives of (meth)acrylic acid such as methyl acrylate, ethyl
acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate,
dimethylaminoethyl acrylate, methyl methacrylate, ethyl
methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl
methacrylate, dimethylaminoethyl methacrylate, acrylonitrile,
methacrylonitrile, acrylamide, or methacrylamide; ethylenically
unsaturated monoolefines such as ethylene, propylene, or butylene;
halogenated vinyls such as vinyl chloride, vinylidene chloride, or
vinyl fluoride; vinyl esters such as vinyl acetate or vinyl
propionate; vinyl ethers such as vinyl methyl ether or vinyl ethyl
ether; vinyl ketones such as vinyl methyl ketone or methyl
isoprophenyl ketone; and a nitrogen-containing vinyl compound such
as 2-vinyl-pyridine, 4-vinyl-pyridine, or N-vinyl-pyrrolidone, and
the like.
[0058] When the primary latex particle is manufactured, a
polymerization initiator and a chain transfer agent may be further
used to efficiently perform the polymerization process.
[0059] Examples of the polymerization initiator may include
persulfates such as potassium persulfate or ammonium persulfate;
azo compounds such as 4,4-azobis(4-cyano valeric acid),
dimethyl-2,2'-azobis(2-methylpropionate),
2,2-azobis(2-amidinopropane)dihydrochloride,
2,2-azobis-2-methyl-N-1,1-bis(hydroxymethyl)-2-hydroxyethylpropioamide,
2,2'-azobis(2,4-dimethylvaleronitrile),
2,2'-azobisisobutyronitrile, or
1,1'-azobis(1-cyclohexancarbonitrile); and peroxides such as
methylethylperoxide, di-t-butylperoxide, acetylperoxide,
dikumylperoxide, lauroylperoxide, benzoylperoxide,
t-butylperoxy-2-ethylhexanoate, di-isopropylperoxydicarbonate, or
di-t-butylperoxyisophthalate, and the like. In addition,
oxidation-reduction initiators prepared by combining these
polymerization initiators and reductants may also be used as the
polymerization initiator.
[0060] The chain transfer agent refers to a material that changes
the type of a chain carrier when a chain reaction occurs. The chain
transfer agent includes a material that induces new chain activity
to be substantially weaker than the existing chain activity. Due to
the chain transfer agent, a polymerization degree of polymerizable
monomers may be reduced so that a novel chain reaction may be
initiated. Owing to the chain transfer agent, the molecular weight
distributions of the polymer may be better controlled.
[0061] The amount of the chain transfer agent may be, for example,
from about 0.1 to about 5 parts by weight, or from about 0.2 to
about 3 parts by weight, or from about 0.5 to about 2.0 parts by
weight, based on 100 parts by weight of the at least one
polymerizable monomer. If the amount of the chain transfer agent is
within these ranges, the molecular weight of the polymer may be
appropriately controlled, and the agglomeration efficiency and
fixing performance may be increased.
[0062] Examples of the chain transfer agent include
sulfur-containing compounds such as dodecanethiol, thioglycolic
acid, thioacetic acid, or mercaptoethanol; phosphorous acid
compounds such as a phosphorous acid or sodium phosphorous acid;
hypophosphorous acid compounds such as a hypophosphorous acid or a
sodium hypophosphorous acid; and alcohols such as methylalcohols,
ethylalcohols, isopropylalcohols, and n-butylalcohols, and the
like. However, the chain transfer agent is not limited to those
materials.
[0063] The primary latex particle may further include a charge
controller. The charge controller may stably support toner on a
development roller with an electrostatic force. Thus, by using the
charge controller, stable and high charging speeds may be obtained.
The charge controller used in one or more embodiments of the
present disclosure may be a negatively charged charge controller or
a positively charged charge controller. Examples of the negatively
charged charge controller may include, but are not limited to, an
organic metal complex such as a chrominum-containing azo complex or
a monoazo metal complex, or chelate compounds; metal-containing
salicylic acid compounds, wherein the metal may be chrominum, iron,
or zinc; and organic metal complexes such as aromatic
hydroxycarboxylic acids or an aromatic dicarboxylic acid. However,
the negatively charged charge controller is not limited to this
list. Examples of the positively charged charge controller may
include, but are not limited to, a modified product such as
nigrosine and a fatty acid metal salt thereof and an onium salt
including a quaternary ammonium salt such as tributylammonium
1-hydroxy-4-naphthosulfonate and tetrabutylammonium
tetrafluoroborate. The negative and positively charged controllers
may be used alone or in combination.
[0064] The primary latex particle obtained as described above may
be mixed with the colorant dispersion and the releasing agent
dispersion to prepare a mixed solution. The colorant dispersion may
be obtained by uniformly dispersing a composition including a
colorant, such as a black colorant, a cyan colorant, a magenta
colorant, or a yellow colorant, and an emulsifier by using an
ultrasonic homogenizer or a micro fluidizer.
[0065] Among colorants used to prepare the colorant dispersion, the
black colorant may be a carbon black or aniline black. For color
toner, at least one colorant may be selected from cyan colorant,
magenta colorant, and yellow colorant, which may be used in
addition to the black colorant.
[0066] The yellow colorant may be a condensation nitrogen compound,
an isoindolinone compound, an anthraquine compound, an azo metal
complex, or an alyl imide compound. Examples of the yellow colorant
include C.I. pigment yellows 12, 13, 14, 17, 62, 74, 83, 93, 94,
95, 109, 110, 111, 128, 129, 147, 168, and 180.
[0067] Examples of the magenta colorant include condensation
nitrogen compounds, anthraquine compounds, quinacridone compounds,
base dye rate compounds, naphthol compounds, benzo imidazole
compounds, thioindigo compounds, and perylene compounds.
Specifically, examples of the magenta colorant include C.I. pigment
reds 2, 3, 5, 6, 7, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 144,
146, 166, 169, 177, 184, 185, 202, 206, 220, 221, and 254.
[0068] Examples of the cyan colorant include but are not limited to
copper phthalocyanie compounds and derivatives thereof, anthraquine
compounds, and base dye rate compounds. Specifically, examples of
the cyan colorant include but are not limited to C.I. pigment blues
1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, and 66.
[0069] These colorants may be used alone or in combination, and may
be selected in consideration of one or more of color, chroma,
brightness, weather resistance, dispersibility in toner, and the
like.
[0070] The amount of the colorant used to prepare the colorant
dispersion may be, for example, from about 0.5 to about 15 parts by
weight, or about 1 to about 12 parts by weight, or about 2 to about
10 parts by weight, based on 100 parts by weight of the toner. If
the colorant used to prepare the colorant dispersion is within
these ranges, a suitable coloring effect as well as sufficient
electrification may be obtained.
[0071] The emulsifier used to prepare the colorant dispersion may
be any known emulsifier. For example, the emulsifier may be an
anionic reactive emulsifier, a non-ionic reactive emulsifier, or a
mixture thereof. The anionic reactive emulsifier may be, for
example, HS-10 (available from Dai-Ichi Kogyo Seiyaku Co., Ltd. of
Tokyo, Japan) or Dowfax.RTM. 2A1 (available from Rhodia Inc. of NJ,
U.S.A.). The non-ionic reactive emulsifier may be RN-10
(manufactured by Dai-Ichi Kogyo Seiyaku Co., Ltd.).
[0072] According to an embodiment, the releasing agent dispersion
that may be used in the preparation of the toner may include a
releasing agent, water, or an emulsifier. The releasing agent may
enable the toner to be fixed to a final image receptor at a
suitably low fixing temperature with desirable final image
durability and abrasion-resistance characteristics. Thus, the
desirable characteristics of toner may be dependent upon the type
and amount of the releasing agent.
[0073] Examples of an available releasing agent may include, for
example, polyethylene-based wax, polypropylene-based wax, silicon
wax, paraffin-based wax, ester-based wax, carnauba wax, or
metallocene wax. The melting point of the releasing agent may be,
for example, from about 50 to about 150.degree. C. The releasing
agent may be physically attached to the toner particles, but may
not be covalently bound to the toner particles.
[0074] The amount of the releasing agent may be from about 1 to
about 20 parts by weight, or about 2 to about 16 parts by weight,
or about 3 to about 12 parts by weight, based on 100 parts by
weight of the toner. If the amount of the releasing agent is within
these ranges, the low-temperature fixing performance and
low-temperature characteristics of the toner may be improved. If
the fixing temperature range is sufficiently large, the costs of
storage and/or the manufacture may be higher.
[0075] The releasing agent may be an ester group-containing wax.
Examples of the ester group-containing wax may include, but are not
limited to, (1) mixtures including ester-based wax and non-ester
based wax; and (2) an ester group-containing wax prepared by adding
an ester group to a non-ester based wax.
[0076] Since an ester group may have high affinity with respect to
the latex component of toner, wax can be uniformly distributed
among the toner particles, thus realizing an effective benefit of
the use of such wax. If however only the ester-based wax is used,
excessive plasticizing reactions may occur. Thus, the inclusion of
the non-ester based wax may result in prevention of such excessive
plasticizing reactions due to its releasing reaction with respect
to the latex. With such a releasing agent of the above described
configurations, the intended development characteristics of toner
may be maintained for a longer period of time.
[0077] Examples of the ester-based wax may include, but are not
limited to, esters of C15-C30 fatty acids and 1 to 5 valence
alcohols, such as behenic acid behenyl, staric acid stearyl,
stearic acid ester of pentaeritritol, or montanic acid glyceride.
Also, if the alcohol component that forms the ester is a monovalent
alcohol, the number of carbon atoms may be from about 10 to 30, and
if the alcohol component that forms ester is a polymeric alcohol,
the number of carbon atoms may be from about 3 to about 10.
[0078] The non-ester based wax may be, for example,
polymethylene-based wax or paraffin-based wax. Examples of the
ester group-containing wax may include, but are not limited to,
mixtures including paraffin-based wax and ester based wax; and
ester group-containing paraffin-based wax. Examples of the ester
group-containing wax may include, but are not limited to, P-280,
P-318 and P-319 (each available from Chukyo Yushi Co., Ltd. Of
Nagoya, Japan).
[0079] If the releasing agent is a mixture including a
paraffin-based wax and an ester based wax, the amount of the
ester-based wax of the releasing agent may be, for example, from
about 5 to about 39 weight %, or about 7 to about 36 weight %, or
about 9 to about 33 weight. %, based on the total weight of the
releasing agent. If the amount of the ester-base wax is within
these ranges, the compatibility of the ester-based wax with respect
to the primary latex particle may be improved. In addition, the
plasticizing characteristics of the toner may be appropriately
controlled and/or the toner may be capable of retaining the proper
development characteristics for a longer period of time.
[0080] Similarly with the emulsifier used in the colorant
dispersion, the emulsifier used in the releasing agent dispersion
may be any known emulsifier, examples of which may include, but are
not limited to, an anionic reactive emulsifier, a non-ionic
reactive emulsifier, and mixtures thereof. The anionic reactive
emulsifier may be, for example, HS-10 (available from Dai-Ichi
Kogyo Seiyaku Co., Ltd. of Tokyo, Japan) or Dowfax.RTM. 2A1
(available from Rhodia Inc. of NJ, U.S.A.). The non-ionic reactive
emulsifier may be RN-10 (manufactured by Dai-Ichi Kogyo Seiyaku
Co., Ltd.).
[0081] According to an embodiment, in preparation of the toner, the
molecular weight, T.sub.g, and rheological characteristics of the
primary latex particles may be appropriately controlled in such a
way that the toner can be fixed at low temperature.
[0082] The primary latex particles, the colorant dispersion and the
releasing agent dispersion as described herein may be mixed to
obtain a mixed solution, to which mixed solution an agglomerating
agent may be added to thereby obtaining an agglomerated toner. For
example, the primary latex particles, the colorant dispersion and
the releasing agent dispersion may be mixed, to which mixture an
agglomerating agent at a pH level that may range from about 0.1 to
about 2.0 may be added to thereby obtain a primary agglomerated
toner having a particle size of 2.5 .mu.m or less. According to an
embodiment, the primary agglomerated toner may act as a core, to
which a secondary latex may be added controlling the pH of the
system to be between about 6 to about 8, for example. After the
particle size of the resultant mixture is maintained constant for
certain period of time, the temperature may be increased to about
90 to 98.degree. C., and the pH level may be decreased to about 5
to 6 to thereby obtain the secondary agglomerated toner
constituting a shell layer.
[0083] The agglomerating agent may include at least one salt
selected from Si-containing metal salts and Fe-containing metal
salts. The Si and Fe-containing metal salts may include, for
example, polysilica iron.
[0084] The secondary latex may be obtained by polymerizing the at
least one polymerizable monomer as described herein. The
polymerization process may be an emulsion polymerization
distribution process. As a result of the emulsion polymerization
distribution process, the secondary latex particles may have a
particle size of about 1 .mu.m or less, for example, from about 100
to about 300 nm. The secondary latex may also include wax, which
may be added in the secondary latex during the polymerization
process.
[0085] The tertiary latex prepared by polymerizing the at least one
polymerizable monomer described herein, may additionally be coated
on the secondary agglomerated toner. By forming the shell layer
using at least one latex selected from the secondary latex and the
tertiary latex, the toner may exhibit high durability and/or better
preservation characteristics during shipping and handling. In this
case, a polymerization inhibitor may be further added to prevent
formation of new latex particles. Starved-feeding conditions, for
example, may be used to appropriately coat a monomer mixed solution
on the toner.
[0086] The secondary agglomerated toner or tertiary agglomerated
toner obtained as described above may be filtered to isolate toner
particles. So isolated toner particles may be dried. Then, an
external additive may be added to the dried toner, controlling the
amount of charge applied, to thereby obtain the final dry
toner.
[0087] The external additive may be, for example, silica or
TiO.sub.2. The amount of the external additive may be from about
1.5 to about 7 parts by weight, or about 2 to about 5 parts by
weight, based on 100 parts by weight of toner prior to the addition
of the external additive. If the amount of the external additive is
within the above ranges, caking of the toner may be prevented
(caking is a phenomenon in which the toner particles may be
attached to each other due to the agglomerating force). In
addition, by controlling the proper amount of the external
additive, the roller contaminations that may result from excessive
external components may be mitigated.
[0088] An imaging method according to an embodiment of the present
disclosure may includes the steps of a) attaching toner to a
surface of a photoreceptor on which an electrostatic latent image
is formed so as to form a visible image; and b) transferring the
visible image onto a transfer medium. The toner may includes latex,
a colorant and a releasing agent, and may further include S, Fe and
Si. The [S]/[Fe] ratio may be from about 5.0.times.10.sup.-4 to
about 5.0.times.10.sup.-2. The [Si]/[Fe] ratio may be from about
5.0.times.10.sup.-4 to about 5.0.times.10.sup.-2, The [S], [Fe] and
[Si] denote the amounts of S, Fe and Si, respectively, measured by
an X-ray fluorescence spectrometry.
[0089] In general, an electrophotographic imaging may include one
or more of a charging process, an exposing process, a developing
process, a transferring process, a fixing process, a cleaning
process and a charge-removing process in order to form an image on
a medium, for example, a sheet of paper.
[0090] During the charging process, a negative charge or a positive
charge may be applied to a photoreceptor by, e.g., using a corona
charger or a charging roller. During the exposing process, the
charged surface of the photoreceptor is selectively discharged to
form a latent image using an optical system such as, for example, a
laser scanner or a diode arrangement. The latent image may be
formed in such a manner that the latent image corresponds to the
desired image to be formed on the final image receptor or medium
(e.g., a sheet of paper). The optical system may use
electromagnetic radiation, such as light, which may be, according
to various embodiments, infrared light radiation, visible light
radiation, or ultra-violet light radiation or a combination
thereof.
[0091] During the developing process, the particles of the toner
having a sufficient charge of a polarity are brought into contact
with the latent image formed on the photoreceptor. Conventionally,
a developing member having the same charge polarity as that of the
toner, i.e. an electrically-biased developing member, may be used.
Consequently, the toner particles may move toward the
photoreceptor, and may selectively be attached to the latent image
portion of the photoreceptor by an electrostatic force to thereby
form the toner image on the photoreceptor.
[0092] During the transferring process, the toner image is
transferred from the photoreceptor to the final image receptor,
e.g., a sheet of paper, or the like. In some cases, as is known to
those skilled in the art, an intermediate transferring element may
be used to transfer the toner image from the photoreceptor to the
final image receptor.
[0093] During the fixing process, the toner image on the final
image receptor is heated so that the particles of the toner are
softened or dissolved, and are fixed to the final image receptor.
Alternatively, the toner image may be fixed to the final image
receptor by compression at high pressure in lieu of or in addition
to the application of the heat.
[0094] During the cleaning process, residual toner remaining on the
photoreceptor is removed.
[0095] Finally, during the charge-removing process, the
photoreceptor is exposed to light having a specific wavelength band
to thereby reduced the charge of the photoreceptor to a uniformly
low value. Thus, the residue of the latent image may be removed,
making the photoreceptor available for a subsequent imaging
cycle.
[0096] A toner supplying unit according to an embodiment of the
present disclosure may include a toner tank for storing a supply of
toner, a supplying part arranged to project inside the toner tank
to discharge the toner from the toner tank and a toner agitating
member rotatably disposed inside the toner tank. According to an
embodiment, the toner agitating member is configured in such a
manner to agitate the toner in almost an entire inner space of the
toner tank, including the locations at the vicinity of the top
surface of the supplying part. The toner used to develop an
electrostatic latent image according to an embodiment may include
latex, a colorant and a releasing agent, and may further include S,
Fe and Si. The [S]/[Fe] ratio according to an embodiment may be
from about 5.0.times.10.sup.-4 to about 5.0.times.10.sup.-2. The
[Si]/[Fe] ratio according to an embodiment may be from about
5.0.times.10.sup.-4 to about 5.0.times.10.sup.-2. The [S], [Fe],
and [Si] denote the amounts of S, Fe and Si, respectively, each of
which may be measured by an X-ray fluorescence spectrometry.
[0097] For example, FIG. 1 shows a toner supplying apparatus 100
according to an embodiment of the present disclosure. The toner
supplying apparatus 100 may include a toner tank 101, a supplying
part 103, a toner-conveying member 105 and a toner-agitating member
110.
[0098] The toner tank 101 may store therein an amount of toner, and
may be formed, for example, in a substantially hollow cylindrical
shape. The supplying part 103 may be disposed at the bottom inner
portion of the toner tank 101, and may operate to discharges the
toner from stored the toner tank 101 out of the toner tank 101. For
example, the supplying part 103 may be arranged at the bottom
portion of the toner tank 101 so as to protrude into the toner tank
101, and may have, according to an embodiment, as shown in FIG. 1,
a pillar shape with a semi-circular cross-section. The supplying
part 103 may include a toner outlet (not shown) through which the
toner is discharged out of the toner tank 101.
[0099] The toner-conveying member 105 may be disposed adjacent the
supplying part 103 at the bottom portion of the toner tank 101. The
toner-conveying member 105 may be formed as, for example, a coil
shaped spring. An end of the toner-conveying member 105 may be
received into the supplying part 103 so that, when the
toner-conveying member 105 rotates, the toner in the toner tank 101
is conveyed to toward and into the supplying part 103 in the
direction indicated by the arrow `A.` The toner conveyed by the
toner-conveying member 105 is discharged to the outside through the
toner outlet of the supplying part 103.
[0100] The toner-agitating member 110 may be rotatably disposed
inside the toner tank 101, and may operated to cause a movement of
the toner in the toner tank 101 in a radial direction. For example,
when the toner-agitating member 110 rotates in the middle of the
toner tank 101, the toner particles in the toner tank 101 are
agitated or stirred. That is, the toner particles may be carried by
the toner-agitating member 110 from the bottom of the toner tank
101 to the top portion of the toner tank 101, and may fall
downwards toward the bottom of the toner tank 101 by its own
weight. Such movement of the toner particles may prevent the
particles from solidifying or clumping together into lumps. The
toner-agitating member 110 may include a rotation shaft 112 and a
toner agitating film 120. The rotation shaft 112 may be rotatably
disposed in the middle of the toner tank 101, and may have a
driving gear (not shown) coaxially coupled with an end of the
rotation shaft 112 projecting from a side of the toner tank 101.
Thus, the rotation of the driving gear causes the rotation shaft
112 to rotate. The rotation shaft 112 may additionally have a wing
plate 114 to help mounting the toner agitating film 120 to the
rotation shaft 112. The wing plate 114 may be formed to be
substantially symmetric about the rotation shaft 112. The toner
agitating film 120 has a width that correspondingly spans the inner
length of the toner tank 101.
[0101] According to an embodiment of the present disclosure, in
order to affectively agitate the toner in the toner tank 101, and
to prevent the toner from collecting and forming lumps in the
vicinity of the top of the supplying part 103, the toner agitating
film 120 may be made to be elastically deformable. For example, the
toner agitating film 120 may be capable of bending when interfered
by a projection inside the toner tank 101, e.g., the supplying part
103. Further, according to an embodiment, the toner agitating film
120 may be cut to form a first agitating part 121 and a second
agitating part 122 so as to allow the first agitating part 121 to
agitate the toner at the vicinity of the top surface the supplying
part 103 in better conformity with the surface of the supplying
part 103. The toner-agitating member 110 of the configuration
described above may thus be capable of reaching substantially the
entire inter volume of the toner tank 101, including the top
surface of the supplying part 103.
[0102] An imaging apparatus according to an embodiment of the
present disclosure may include an image carrier an image forming
unit that forms an electrostatic latent image on a surface of the
image carrier a toner receiving unit receiving a supply of toner
therein, a toner supplying unit that supplies the toner onto the
surface of the image carrier to develop the electrostatic latent
image on the surface of the image carrier into a toner image and a
toner transferring unit that transfers the toner image to a medium
from the surface of the image carrier. The toner may include a
latex, a colorant and a releasing agent, and may further include S,
Fe and Si. The [S]/[Fe] ratio may be from about 5.0.times.10.sup.-4
to about 5.0.times.10.sup.-2. The [Si]/[Fe] ratio may be from about
5.0.times.10.sup.-4 to about 5.0.times.10.sup.-2. The [S], [Fe] and
[Si] denote the amounts of S, Fe and Si, respectively, each of
which may be measured by an X-ray fluorescence spectrometry.
[0103] FIG. 2 shows an example of a non-contact development type
imaging apparatus including toner prepared using a method according
to an embodiment of the present disclosure.
[0104] In a developing device 204, a nonmagnetic one-component
developer (for example, toner) 208 may be supplied to a developing
roller 205 by a supply roller 206 that may be formed of an elastic
material, such as polyurethane foam or sponge. The developer 208
supplied to the developing roller 205 may reach a contact portion
between a developer controlling blade 207 and the developing roller
205 due to the rotation of the developing roller 205. The developer
controlling blade 207 may be formed of an elastic material, such
as, for example, metal or rubber. When the developer 208 passes
through the contact portion between the developer controlling blade
207 and the developing roller 205, the developer 208 is formed into
a thin layer, which may have a substantially uniform thickness, and
which may be charged to certain potential level. So formed and
charged layer of developer 208 is brought to a development region
of a photoreceptor 201, which is an example of an image carrier, to
develop the latent image being carried on the photoreceptor 201.
The latent image is formed by exposing to a light 203 selective
portions of a uniformly charged surface of the photoreceptor 201 to
create a pattern of charge potential differences across the surface
of the photoreceptor 201 corresponding to the intended image, and
may thus be invisible prior to the development thereof.
[0105] The developing roller 205 may be arranged to face the
photoreceptor 201 and to be spaced apart from the photoreceptor 201
by a predetermined distance. The developing roller and the
photoreceptor 201 may be made rotate in rotational directions
opposite to each other. For example, the developing roller 205 may
be made to rotate in the counter-clockwise direction while the
photoreceptor 201 is made to rotate in the clockwise direction.
[0106] The developer 208, which has been transferred to the
development region of the photoreceptor 201, develops the latent
image into visible form by an electrical or electrostatic force
generated by the potential difference between the developing roller
205, to which a voltage that may include a direct current (DC) bias
and/or alternating current (AC) voltage may be applied, and the
latent potential of the photoreceptor 201. The developer 208
becomes transferred from the developing roller 205 to selective
portions of the photoreceptor 201 according to the potential
difference in the latent image so as to form a visible developer
image on the photoreceptor 201. Prior to the formation of the
latent image by exposure to the light 203, the surface of the
photoreceptor 201 may be charged to a uniform potential by a
charging unit 202 so as to provide a clean canvas on which the
latent image can be drawn.
[0107] Subsequent to the development of the latent image, the
developer 208, which has been transferred to the photoreceptor 201,
reaches a transfer unit 209 due to the rotation direction of the
photoreceptor 201, and is transferred from the photoreceptor 201 to
a print medium 213 that passes between the photoreceptor 201 and
the transfer unit 209, which may be, e.g., a roller to which a high
voltage having a polarity opposite to the charged developer 208 may
be applied. The residual charges remaining on the photoreceptor 201
may then be removed, for example, by a light exposure or by corona
discharging subsequent to the transfer of the toner image to the
print medium 213.
[0108] The print medium 213 carrying the transferred toner image
may be made to pass through a high temperature and high pressure
fusing device (not shown), causing the developer 208 of the toner
image to be fused to the print medium 213 and to thereby complete
the formation of the image. The non-developed, residual developer
208 remaining residual on the developing roller 205 may be
collected by the supply roller 206 that contacts the developing
roller 205. The non-transferred, residual developer 208' remaining
residual on the photoreceptor 201 may be collected by a cleaning
blade 210 into a waste developer container. The above-described
image forming processes may be repeated as necessary to form
additional images.
[0109] For further illustration of various aspects of the present
disclosure, several specific examples will now be described. It
should be understood however that these examples are for
illustrative purposes only, and are not intended to limit the scope
of the present disclosure.
EXAMPLES
[0110] SEM images of toners prepared according to the following
examples may be obtained to identity shapes of the toners. The
circularity of the toners can be measured, for example, using an
SYSMEX FPIA-3000 using the equation below as previously
described.
Circularity=2.times.(.pi..times.area).sup.0.5/circumference.
[0111] The circularity may be from 0 to 1. As the circularity
approaches 1, the toner particle shape becomes more circular.
Example 1
Synthesis of Primary Latex Particles
[0112] 1,000 g of a polymerizable monomer mixed solution
(styrene/n-butyl acrylate weight ratio of 75.3/24.7), 33 g of
b-carboxyethylacrylate (Sipomer, Rhodia), 4.2 g of A-decandiol
diacrylate constituting a crosslinker, 7.5 g of 1-dodecanethiol
acting constituting a chain transfer agent (CTA), and 500 g of
sodium dodecyl sulfate (Aldrich) aqueous solution (2% compared to
water) constituting an emulsifier are added to a 3 L beaker, and
the mixture is stirred to prepare a polymerizable
monomer-emulsified solution. Separately, 18 g of ammonium
persulfate (APS) constituting an initiator and 1,160 g of sodium
dodecyl sulfate (Aldrich) aqueous solution (0.13% with respect to
water) constituting an emulsifier are added to a 3 L
double-jacketed reactor heated to a temperature of 75.degree. C.
While stirring the mixture including APS and sodium dodecyl
sulfate, the prepared polymerizable monomer emulsified-solution is
slowly dropped into the mixture for at least two hours. The
reaction is performed for about 8 hours at this reaction
temperature to obtain the primary latex particles. The particle
size of the primary latex particles is measured by using a light
scattering-type Horiba 910. The average particle size measured is
from about 150 to about 200 nm. In this case, the toner
concentration is 42.3%.
[0113] Preparation of Colorant Dispersion
[0114] 10 g of an anionic reactive emulsifier (e.g., HS-10;
Dai-Ichi Kogyo) and 60 g of cyan colorant are loaded into a milling
bath, to which 400 g of glass beads having a diameter of 0.8 to 1
mm is added, and a milling operation is performed at room
temperature, thereby obtaining a cyan colorant dispersion. The
homogenizer used in this experiment is an ultrasonic homogenizer
(e.g., VCX750 available from Sonic & Materials, Inc. of
Newtown, Conn., U.S.A.).
[0115] Agglomeration and Preparation of Toner
[0116] 30 g of a nitric acid (0.3 mol), and 15 g of 12% PSI-100
(available from Suido Kiko Kaisha, Ltd. of Tokyo, Japan)
constituting an agglomerating, agent are added to a mixed solution
including 500 g of de-ionized water, 150 g of the primary latex
particles constituting a core, 35 g of 19.5% cyan colorant
dispersion (HS-10 100%), and 28 g of 35% wax dispersion P-419
(available from Chukyo Yushi Co., Ltd. of Nagoya, Japan) in a 1 L
reactor. The mixture is stirred using a homogenizer at a rate of
11,000 rpm for 6 minutes, thereby obtaining a primary agglomerated
toner having a particle size of 1.5 to 2.5 .mu.m. The resultant
mixed solution is added to a 1 L double-jacketed reactor and the
temperature is increased by 0.5.degree. C. per minute from room
temperature to 51.5.degree. C. (e.g., a temperature equal to or
higher than T.sub.g-5 degree of latex). When the volume average
diameter of the primary agglomerated toner reached about 6.3 .mu.m,
50 g of a secondary latex, obtained by polymerizing
polystyrene-based polymerizable monomers, is added thereto. When
the volume average particle diameter of the reaction solution is
from about 6.5 to 7.0 .mu.m, NaOH (1 mol) is added to the reaction
solution to control the pH level of the reaction solution to be
about 7. When the volume average particle diameter is maintained
constant for 10 minutes, the temperature is increased to 96.degree.
C. at a rate of 0.5.degree. C./min. When the temperature is about
96.degree. C., nitric acid (0.3 mol) is added to the reaction
solution to control the pH level of the reaction solution to be
about 5.7. The reaction may be performed for 3 to 5 hours to obtain
a secondary agglomerated toner having potato-like shaped particles
having a particle size of 6.5 to 7 .mu.m. The agglomerated reaction
solution may be cooled to a temperature lower than T.sub.g, and a
filtering operation is performed to isolate toner particles, which
toner particles are then dried.
[0117] External additives are added to the toner by adding 0.5
parts by weight of NX-90 (available from Nippon Aerosil Co., Ltd.
of Osaka, Japan), 1.0 parts by weight of RX-200 (Nippon Aerosil),
and 0.5 parts by weight of SW-100 (available from Titan Kogyo, Ltd.
of Ube, Japan) to 100 parts by weight of the dried toner particles.
The mixture is stirred using a mixer (e.g., using a KM-LS2K
available from Dae Hwa Tech Co., Ltd. of Busan, Korea) at a rate of
8,000 rpm for 4 minutes. The resultant toner has a volume average
particle diameter from about 6.5 to about 7.0 .mu.m. GSDp and GSDv
of the final toner are 1.272 and 1.221, respectively. The
circularity of the final toner is 0.972.
Example 2
Preparation of Toner
[0118] Toner is prepared in the same manner as in Example 1, except
that 15 g of nitric acid (0.3 mol) and 15 g of PSI-025 (available
from Suido Kiko Kaisha, Ltd. of Tokyo, Japan) constituting an
agglomerating agent are used. GSDp and GSDv of the toner are 1.271
and 1.226, respectively. The circularity of the toner is 0.970.
Example 3
Preparation of Toner
[0119] Toner is prepared in the same manner as in Example 1, except
that 5 g of a nitric acid (0.3 mol) and 15 g of PSI-200 (available
from Suido Kiko Kaisha, Ltd.) constituting an agglomerating agent
are used. GSDp and GSDv of the toner are 1.267 and 1.214,
respectively. The circularity of the toner is 0.971.
Example 4
Preparation of Toner
[0120] Toner is prepared in the same manner as in Example 1, except
that a black colorant is used instead of the cyan colorant. GSDp
and GSDv of the toner are 1.265 and 1.221, respectively. The
circularity of the toner is 0.973.
Example 5
Preparation of Toner
[0121] Toner is prepared in the same manner as in Example 1, except
that 30 g of nitric acid (0.3 mol) and 15 g of PSI-100 (available
from Suido Kiko Kaisha, Ltd.) are used as an agglomerating agent.
GSDp and GSDv of the toner are 1.294 and 1.257, respectively. The
circularity of the toner is 0.971.
Example 6
Preparation of Toner
[0122] Toner is prepared in the same manner as in Example 1, except
that polyaluminum chloride (PAC), 6 g of a nitric acid (0.3 mol)
and 3 g of PSI-100 (available from Suido Kiko Kaisha, Ltd.) are
used as the agglomerating agent. GSDp and GSDv of the toner are
1.274 and 1.227, respectively. The circularity of the toner is
0.971.
Comparative Example 1
[0123] Toner is prepared in the same manner as in Example 1, except
that PAC, 3 g of a nitric acid (0.3 mol) and 1.4 g of PSI-100
(available from Suido Kiko Kaisha, Ltd.) are used as an
agglomerating agent. GSDp and GSDv of the toner are 1.260 and
1.213, respectively. The circularity of the toner is 0.972.
Comparative Example 2
[0124] Toner is prepared in the same manner as in Example 1, except
that PAC is used as an agglomerating agent. GSDp and GSDv of the
toner are 1.279 and 1.216, respectively. The circularity of the
toner is 0.970.
Comparative Example 3
[0125] Toner is prepared in the same manner as in Example 1, except
that 25 g of sodium hydroxide (1.0 mol) and 75 g of PSI-025
(available from Suido Kiko Kaisha, Ltd.) acting as an agglomerating
agent are used. GSDp and GSDv of the toner are 1.369 and 2.953,
respectively. The circularity of the toner is 0.965.
Comparative Example 4
[0126] Toner is prepared in the same manner as in Example 1, except
that 0.80 g of PSI-025 (available from Suido Kiko Kaisha, Ltd.) is
used as an agglomerating agent. GSDp and GSDv of the toner are
1.509 and 1.312, respectively. The circularity of the toner is
0.975.
Example 8
Toner Evaluation
[0127] X-ray Fluorescence Measurement
[0128] An X-ray fluorescence measurement of each of the samples is
performed using an energy dispersive X-ray spectrometer (EDX-720
available from Shimadzu Corporation of Kyoto, Japan). The X-ray
tube voltage is 50 kV, and the amounts of samples that are molded
are 3 g.+-.0.01 g. For each sample, the [S]/[Fe] and [Si]/[Fe]
ratios are calculated using the amounts obtained by the X-ray
fluorescence measurement and the intensity (unit: cps/uA).
[0129] Unpleasant Odor Evaluation
[0130] 10 female and male adults participated in a blind unpleasant
odor test to evaluate the samples. Each of the samples is loaded in
an amount of about 10 g into a 50 mL container, and the container
is sealed and placed in an oven at a temperature of 42.degree. C.
for 2 hours. The heated container is cooled to room temperature
(about 25.degree. C.), and the test is performed. The 50 mL
container is opened in an NN (room temperature and room
humidity)-environment lab. (.circleincircle. denotes a case in
which no one sensed the unique unpleasant odor of a S compound;
.smallcircle. denotes a case in which 1-3 of the participants
managed to sense the unique unpleasant odor of a S compound;
.DELTA. denotes a case in which 4-7 of the participants easily
sensed the unique unpleasant odor of a S compound; and x denotes a
case in which most participants (8-10) easily sensed the unique
unpleasant odor of a S compound)
[0131] .circleincircle.: No problems occurred when used.
[0132] .smallcircle.: Although no problems occurred when used,
toner quality was lower than that of .circleincircle..
[0133] .DELTA.: Unpleasant odor was generated under particular
circumstances.
[0134] x: Cannot be used.
[0135] Agglomeration Evaluation
[0136] In consideration of the toner particle diameter distribution
and unreacted (un-agglomerated) latex, this test is performed
before external additives are added. Agglomeration evaluation
conditions are as follows: the amount of un-agglomerated latex is
determined according to a degree of transparency of a cleansing
solution after the cleansing solution is used for cleansing the
prepared toner. When the cleansing solution is transparent, such
that a bottom of a container containing the cleansing solution
could be seen, it is determined that no residual latex existed.
When the cleansing solution is not transparent, such that a bottom
of a container containing the cleansing solution could not be seen,
it is determined that the residual latex existed in small
amounts.
[0137] .circleincircle.: each of GSDv and GSDp was 1.30 or less,
and no un-agglomerated latex existed
[0138] .smallcircle.: each of GSDv and GSDp was 1.30 or less, and
the un-agglomerated latex existed in small amounts
[0139] .DELTA.: at least one of GSDv and GSDp was greater than
1.30, and no un-agglomerated latex existed
[0140] x: at least one of GSDv and GSDp was greater than 1.30, and
the un-agglomerated latex existed in small amounts
TABLE-US-00002 TABLE 2 X-ray Fluorescence Type of pH when
measurement Unpleasant Agglomerating Agglomerating results Odor
Agglomeration agent agent is added [S]/[Fe] [Si]/[Fe] Evaluation
Evaluation Example 1 PSI-100 0.79 6.2 .times. 10.sup.-3 4.1 .times.
10.sup.-3 .circleincircle. .circleincircle. Example 2 PSI-025 1.07
3.4 .times. 10.sup.-3 1.9 .times. 10.sup.-3 .circleincircle.
.circleincircle. Example 3 PSI-200 1.33 1.02 .times. 10.sup.-2 7.4
.times. 10.sup.-3 .circleincircle. .circleincircle. Example 4
PSI-100 0.82 7.3 .times. 10.sup.-3 5.2 .times. 10.sup.-3
.circleincircle. .circleincircle. Example 5 PSI-100 0.80 3.2
.times. 10.sup.-2 2.1 .times. 10.sup.-2 .circleincircle.
.circleincircle. Example 6 PAC + PSI-100 0.83 1.3 .times. 10.sup.-3
8.0 .times. 10.sup.-4 .largecircle. .circleincircle. Comparative
PAC + PSI-100 0.85 6.4 .times. 10.sup.-2 4.0 .times. 10.sup.-2
.DELTA. .circleincircle. Example 1 Comparative PAC 0.96 -- -- X
.circleincircle. Example 2 Comparative PSI-025 2.90 6.0 .times.
10.sup.-4 3.9 .times. 10.sup.-4 .circleincircle. .DELTA. Example 3
Comparative PSI-025 1.04 6.2 .times. 10.sup.-2 3.9 .times.
10.sup.-2 X X Example 4
[0141] Referring to Table 2, when the toners for developing an
electrostatic latent image manufactured according to Examples 1 to
6 each having a [S]/[Fe] ratio ranging from about
5.0.times.10.sup.-4 to about 5.0.times.10.sup.-2 and a [Si]/[Fe]
ratio that ranges from about 5.0.times.10.sup.-4 to about
5.0.times.10.sup.-2 did not cause problems in the unpleasant odor
evaluation. As discussed previously, the respective amounts of S,
Fe and Si, i.e., [S], [Fe] and [Si], were measured by an X-ray
fluorescence spectrometry.
[0142] However, when the [S]/[Fe] ratio is outside the range
described above, and/or the [Si]/[Fe] ratio is outside the range
described above, that is, the toners manufactured according to
Comparative Examples 1, 2 and 4, the toners produced an unpleasant
odor. With regard to Comparative Example 3, an unpleasant odor is
not emitted because Fe is used in excessive amounts. However, since
the agglomerating agent is used in excessive amounts, the toner
particle diameter distribution may be wider, or the agglomeration
characteristics of the toner may be degraded. For example, the
amount of the residual un-agglomerated latex may be increased.
Thus, despite the absence of an unpleasant odor, the toner
manufactured according to Comparative Example 3 may not be suitable
for use as a toner.
[0143] As described herein, according to the embodiments of the
present disclosure, a toner that does not generate an unpleasant
odor while maintaining other properties of the toner can be
manufactured.
[0144] While the present disclosure has been particularly shown and
described with reference to several embodiments thereof, it will be
understood by those of ordinary skill in the art that various
changes in form and details may be made thereto without departing
from the principles and spirit of the present disclosure, the
proper scope of which is defined in the following claims and their
equivalents.
* * * * *